The proposed research seeks to understand 1. how electrical conditions influence the evolution of animal communication systems and 2. how physiological properties of sensory receptors affect stimulus perception and the evolution of communication signals. Using electrical communication as a model system, the research has two major approaches: field studies of electrical communication among Mormyriform fishes in Africa; and electrophysiological studies of stimulus filtering in electroreception. African field experience will benefit from previous research with electric communication among gymnotid fish from South America. Convergent evolution--a unique tool of research provided by the separate evolution of electric organs and receptors on two continents--will be explored as it related to social signaling. Field work will emphasize 1. signal transmission, 2. signaler identification, 3. social signaling and 4. ecology of electric fish. Following up on recent research in electroreception, studies will be made of stimulus filtering by tuberous electroreceptors using 1. a comparative study of filtering in several distinctive species, 2. an exploration of central control of stimulus filtering, and 3. an exploration of plasticity of stimulus filtering.